卷叶水稻的光分布模拟及适宜叶面卷曲度分析

 以叶面高度卷曲的水稻组合两优E32、中等卷曲组合两优培九和不卷曲组合汕优63为材料，引入叶面卷曲度因子，用有效叶面积指数代替传统的叶面积指数（LAI），模拟水稻冠层内的辐射传输，比较了不同叶面卷曲度因子材料的光合有效辐射截获率、转化率和利用率，探讨了不同材料的最适叶面卷曲度及最佳群体密度。结果表明，有效叶面积指数比传统的叶面积指数能更准确地预测冠层内光合有效辐射的分布。两优E32叶片过度卷曲，有效叶面积指数偏小，光合有效辐射利用率不高；而汕优63叶片平展且披散，下层叶片长期受光条件不良，光合能力弱，光合有效辐射利用率也不高。相比之下，两优培九的光合有效辐射截获率、转换率分布较为合理，光合有效辐射的利用率也较高，最适LAI为7.6，与常规栽培条件下的群体密度（LAI=7.9）接近。两优E32和汕优63的最适LAI分别为9.8和6.2，而常规栽培条件下的群体密度过小或过大，导致光合有效辐射利用率不高。利用孕穗期至齐穗期有效辐射利用率的实测值，通过输入不同的叶面卷曲度因子，得到两优E32、两优培九和汕优63的最佳叶面卷曲度因子分别为0.12、0.11和0.08，均非常接近两优培九的实际叶面卷曲度因子（0.11）。

Simulation on Photosynthetically Active Radiation Distributing in Rice Canopy With Rolled Leaves and Its Optimum Leaf Rolling Index

By replacing leaf area index(LAI)with effective leaf area index(ELAI)through introduction of leaf rolling index(LRI),the distribution of photosynthetically active radiation(PAR)in the canopy of three hybrid rice combinations,Liangyou E32 with high leaf rolling index,Liangyoupeijiu with medium leaf rolling index and Shanyou 63 with non-rolled(normal)leaves,was simulated.The results showed that the model based on ELAI could predict more accurately than that based on LAI.PAR interception,conversion and utilization efficiency of the three combinations were studied and their each optimal LRI and LAI were evaluated.The PAR utilization efficiency of Liangyou E32 was lower due to excessive rolled leaves and less ELAI,and that of Shanyou 63 was also lower because of the faulty PAR interception and lower photosynthetic rate and saturation point at lower layer in the canopy.Compared with the other two combinations,Liangyoupeijiu showed more appropriate distribution of PAR interception conversion efficiency in canopy with higher PAR utilization efficiency.The optimal LRI and LAI for Liangyoupeijiu were 0.11 and 7.6,respectively,which were close to the observed values,0.11 and 7.9,respectively.However,the optimum LAI of 9.8 for Liangyou E32 and 6.2 for Shanyou 63 were larger or smaller than those under the current plant density,which led to lower PAR utilization efficiency.The optimum LRI of the three hybrids was concluded as 0.08-0.12,close to the actual LRI of Liangyoupeijiu.